Work out your area first, you will need to laminate both sides of the new plywood. Allow for 2 layers underneath and 3 layers on top so five times your floor plan area. I tend to use 450grm CSM but you could drop to 300grm especially underneath as it will not use as much resin. Hardly worth the saving on a job like yours though.

Buy some disposable plastic pint pots from a supermarket they are great for mixing a handy volume of resin, you can brush from these and drop them in the bin when empty. You will need 2.5 - 5 litres of Acetone for prepping, mixing and cleaning. I buy resin in 20kg kegs as it works out cheaper, you will be buying probably in multiples of 2.5kg avoid the expensive 1kg ones, you can always use the excess rather than trying to stretch too little. If you are new to glass fibre laminating you will tend to use a lot of resin so buy over rather than under.

Pigment, choose carefully. If you want orange check the shade don't just order a general orange as it can be far too yellow.